Posts Tagged ‘Handicap’

Expected Wins – 2016 season

January 27, 2017

In 2015 we introduced the idea of Expected Wins (“Expt Wins”) which reviews a team’s season, on a game by game basis, versus what they were expected to do using bookmaker’s odds. There are undoubtedly drawbacks to this which are expanded upon in the original article (here) however it is an interesting prism to view the season through rather than just looking at those that had a “good Championship”

2016 Top Performers

Team Games played Wins Win % Expt Wins above/below Expt Pts Win % rank Expt Wins rank
Clare 14 9 64% 5.465 +3.535 5 1
Dublin 16 15 94% 12.218 +2.782 1 2
Longford 10 5 50% 3.430 +1.570 =11 3
Louth 11 7 64% 5.483 +1.517 6 4
Carlow 10 4 40% 2.750 +1.250 =18 5

As can be expected those teams that have a good winning percentage are also high up on the Expt Wins ranking. Keep winning and you’ll consistently outperform your odds and thus your Expected Wins. Dublin, despite their very short odds at times and thus very high Expt Win total, being the poster child for this.

The two teams that had the most unexpected run in the Championship – Clare and Tipperary – are both comfortably in the top10 (Tipperary are joint 6th with an Expt Win total of +0.889) as they made a mockery of their odds at times. Indeed Clare also had an excellent league campaign, winning five of their eight games and picking up the Division 3 title, which helped them climb to first in the table.

Longford had a lesser league campaign winning three of their seven games but completed one of the shocks of the Championship beating Monaghan away in the qualifiers at odds of 15/2 which accounted for nearly all their positive Expt Win total. Removing the bookmaker’s margin they were expected to win that game ~8% of the time.

Perhaps the biggest surprise is Carlow. They won three games in the league for the first time since 2012 (when there was an extra game as Kilkenny played boosting everyone’s win volume in Division4!) whilst also recording only their second Championship win since the end of the 2011 campaign. You won’t read about Carlow having a good season anywhere … but the fact they outperformed expectations to such an extent should ensure it is considered as such.

Versus the Handicap

Another way to review a team is through the prism of the handicap. Bookmakers will tell you that they set the handicap line according to what they think their customers will back, thus giving them an even book, rather than the respective merits of the teams. Public perception, along with the strengths of the team, thus feeds into the handicap line. Even still it is quite a good barometer of how teams are expected to perform. So how did teams fare against the handicap and also the two rankings above?

Team Games played Games covered Cover % Cover Rank Win % rank Expt Wins rank
Kerry 13 10 76.9% 1 =2 =6
Louth 11 8 72.7% =2 6 4
Fermanagh 11 8 72.7% =2 =20 11
Tyrone 13 8 61.5% =4 =2 =8
Cavan 13 8 61.5% =4 =10 9

Only Louth appear in the Top5 of both the Expt Win and Handicap rankings though in truth all 5 that covered the handicaps most often were also high up in the Expt Wins Ranking.

Fermanagh may have only won four of their 11 games in 2016 (two at home in the league, the home win versus Antrim in the Ulster Championship and then away to Wexford in the qualifiers) however they were a tough nut to crack with only 3 teams managing to beat them on the handicap (Cavan winning by 6 in Brewster Park, Derry in the opening round of the league and Donegal in the Ulster championship). Indeed that Cavan game was the only one of the five that Fermanagh played at home where they failed to cover the handicap. We saw something similar in 2015 when they covered in five of the six games played at home. Fortress Brewster!

But this all buries the lead. Kerry were excellent against the handicap (see Note1) where they only failed to cover in the opening two rounds of the league, against Dublin and Roscommon, and again in the league final. We have seen a phenomenon of double digit favourites tending not to cover (see Note2) but when a big favourite in 2016 (11 + 10 versus Clare in their two games and 9 versus Tipperary in the Munster final) Kerry covered each time. They don’t get dragged down by “lesser” opposition – they play to their own level.

2016 Worst Performers

Team Games played Wins Win % Expt Wins above/below Expt Pts Win % rank Expt Wins rank
Cork 11 5 45% 6.617 -1.617 15 28
Limerick 10 1 10% 2.799 -1.799 31 29
Monaghan 14 4 36% 5.829 -1.829 =20 30
Down 9 0 0% 1.960 -1.960 32 31
Armagh 10 2 20% 3.963 -1.963 29 32

It is no surprise, given that league games can make up 60% to 70% of a poor team’s season that relegated teams feature heavily here. Between them Cork, Down, Armagh & Limerick mustered five wins from their 28 league games.

Down didn’t register a win in 2016 however Armagh, despite winning two games, came out slightly worse on Expt Wins. This is due to the fact that they were expected to be competitive in Division2. Outside of the Round6 game away to Tyrone, when the reality of their form was beginning to catch up with their odds, the largest price they were in any league game was 7/4. They also played three (see Note3) Championship games where they were given a good chance of winning each (2/1, 11/10 & 9/4) but came away with three losses.

Down on the other hand started slowly and continued to plummet. They may have lost all nine games but were only ever expected to win ~1.96 of those. Armagh were expected to win ~3.96 of theirs.

Monaghan had an average league campaign winning three of their seven games when they were expected to win ~3.1 games. Their issues were in the Championship where they had two 50:50 games with Donegal but won neither and then lost as 1/12 favourites at home to Longford. That loss alone equates to -0.893 Expt Wins.

Versus the handicap

Team Games played Games covered Cover % Cover Rank Win % rank Expt Wins rank
Laois 12 4 33.3% =28 =24 =23
Derry 12 4 33.3% =28 17 25
Waterford 9 3 33.3% =28 28 27
Down 9 3 33.3% =28 32 31
Wicklow 9 2 22.2% 32 =24 21

This is the “hope you weren’t relying on these guys throughout the year” listing.

Similar to the positive performers table there is only one team – Down – that appears in the worst list for both Expt Wins and handicap rankings. Again like the top performers those at the bottom of the handicap ranking are also in the bottom third of the Expt Wins ranking.

Waterford & Wicklow appear in the bottom 5 for the second year running. Combining 2015 & 2016 they are running at a 28% cover rate (9 games from 32).

We have already seen one of the teams relegated from Division2 – Armagh – appear in the “worst performing” category so it’s no surprise to see the other two teams that filled out the bottom three of that division make an appearance here. Division2 was seen as ultra-competitive at the start of the year and this was followed through with a high volume of games with a close handicap (see Note4). Once teams started to underperform they were going to struggle against the handicap.

Notes

Note1; what is more remarkable, and a cautionary tale re taking trends at face value, is that Kerry were in the bottom two in this metric in 2015. Then they covered in 31% (4 out of 13) of their games. We must always remember that we are dealing with very small sample sizes (and margins) here where a point or two can have a huge effect.

Note2; twenty teams since the start of the 2015 league campaign have started as double digit favourites. Only 7 (35%) have managed to cover this.

Note3; Although the first Laois game was declared null and void it was played as if it was a Championship game and we have odds & a result for it so it is included overall.

Note4; 86% (25 games out of 29) had a handicap of 2 or less in Division2. This was 52% for Division1, 83% for Division3 and 48% for Division4

Thinking out loud; In GAA betting the handicap is intrinsically linked to the match price. If those with high Expt Wins (essentially odds on shots) generally cover at a better rate, and the corollary is true for those with low Expt Wins are the linkages between match price and handicap line “out”?

Advertisements

Expected Wins; how teams fared versus their odds

January 11, 2016

Once September rolls around only one or two teams will deem their year as being successful. In 2015 Dublin had a year of years winning the league, Leinster and the All Ireland (do we throw in the O’Byrne cup?). Monaghan winning Ulster made for a successful season whilst there is an honourable mention for Fermanagh with promotion to Division2 and the quarter final appearance. But what about the rest?

If the league is a means to an end for the majority, and the All Ireland and Provincial championships are regularly shared by the same teams, how do we measure the remainder’s performance? Or indeed how do we judge a team like Tyrone that got relegated, fell short in Ulster but rallied to get to the All Ireland semi-final? One way is to compare a team’s results against how bookmaker’s thought they should fare.

Bookmakers give odds on all games. The main markets are match odds and handicap. Any bookmaker worth their salt will tell you that though all odds can be converted into a percentage chance of winning this is not their primary aim when setting the line. They are not trying to exactly predict the likelihood of an outcome but rather set a line that will encourage multi way action on the game. This then enables them to have relatively evenly split betting on all outcomes and they can take the built in margin.

Still these lines are a very good proxy for how a team is expected to perform and the cumulative odds can thus be used to extract just how many games a team won above, or below, what was expected. Thus we create an Expected Wins (Exp Wins) metric.

Expected Wins

All odds for a game were converted to an Exp Win (see methodology in Note2 below) and then teams ranked according to how many wins they obtained in the League & Championship above this mark

Exp Win Top10

It comes as no surprise that seven of the top ten teams in pure win percentage appear in the top ten based on Exp Wins. Fermanagh and Monaghan are up there given their aforementioned successful seasons. Longford also had a good year winning 9 of their 13 games. In fact on pure winning percentage they finished second in the country behind Dublin’s 75%.

But what of the remainder? The biggest surprise by far was Limerick. They only won three games in total, ranking them in the bottom third on pure wins alone, but were 7th when compared to their Exp Wins. How so?

Limerick breakdownv2

They were the outsider in all seven of their league games but won three. From those seven games the bookmakers expected them to win 1.87. They outperformed their expected wins by more than a full game. In the Championship they lost by two points away to Clare in a game that had Clare favoured by two and then walked into Tyrone in the first round of the back door. The positive Exp Win total they accumulated in the league was not too badly dented by these two losses – especially the Tyrone one where they were huge outsiders.

Sligo were a bit of a surprise given that they only won four games but again they were quite large underdogs when beating Roscommon in the Championship and complete outsiders in the next two games against Tyrone & Mayo. Given the very low combined Exp Wins from those three games (0.39) that one victory against Roscommon puts them in positive territory for the Championship alone.

Against the Spread

Another way of tracking a team’s performance is to see if they covered the bookmaker’s handicap; or what their ATS (against the spread) was in American parlance. We would expect some cross over with the best performers in the Expected Win list but crucially you don’t have to win a game to beat this performance metric – only play above an expected standard

ATS Top 10

Again six of the teams that appeared in the Exp Wins top ten re-appear. A number of the teams, such as Limerick, Sligo, Fermanagh & Monaghan we have touched upon previously but there are a few surprises. Mayo, despite being a very high profile team, would have been a profitable one to follow on the handicap. Cork, for all the negativity following the losses to Kerry & Kildare, were also profitable but it is London & Leitrim that jump out. Between them they won four games all season but it could be argued they had a pretty good year; their performance exceeded expectations in 12 of their combined 18 games.

London only won one of their nine games all year but managed to cover the handicap on six occasions. Narrow that further and they covered the handicap in five of their seven league games including all three that they played away. You would never state that London had a good season but from a performance perspective we should probably cut them some slack. They performed well above expectation.

Worst Performances

Exp Win Bottom5

Originally the above table was going to be the bottom five but I expanded it to catch two of the bigger fish.

Some of the lower lights – Carlow, Wicklow & Waterford – being down here is not really a surprise given just how few games they won. However it does indicate that perhaps the bookmakers were generally over rating them despite their poor form.

Laois were particularly poor but looking purely at their Championship form they beat Carlow when their Exp Win was 0.86 so get very little credit for that and then had a further three games failing to win any of them when the combined Exp Win was 1.75.

Given they were relegated from Division 1 with just the one win from seven it is perhaps no surprise to see Tyrone down here.

Kerry won seven games throughout the year but were expected to win eight. Creating a league/Championship split Kerry had an Expected win of -0.81 in the league and -0.19 in the Championship. Their Championship was slightly less underwhelming than their league (I kid – sort of!)

ATS Bottom 5

Three of those that appeared in the worst Exp Win table re-appear when we look at the worst performances against the handicap. Wicklow and Waterford not only failed to win enough games but also played poorly in their losses covering a combined four handicaps over 18 games. Given that they won seven games but were only an outsider once during the year – and that a slight outsider in the final against Dublin – it is no surprise that Kerry are again represented.

They had, all told, a good year but were consistently over valued by the bookmakers. Or conversely the bookmakers kept their odds short as the public’s perception of Kerry was that they were performing better than they actually were.

APPENDIX

Note 1; there can be quite a difference in bookmaker’s odds. The odds used for this piece were taken primarily from Paddy Power rather than taking the best prices available across all bookmakers. The main reason for this was laziness on my part as it meant just one source rather than hopping around sites.

When you take the price can also be important. Lines do move. However they were generally taken on Saturday or Sunday morning when any early moves had been accounted for.

Note2; generally speaking the margin on GAA match odds is 109% with lesser games getting up to 112%. A typical line in a close game would be 10/11 (home team), 15/2 (draw) & 6/5 (away team) which equals a book of 109.6%. To make this, and all games, come in at 100% – and remove the bookmaker’s margin – I extracted 3% from each outcome. There is a valid argument that this should be more nuanced (take less off the draw perhaps) but for now it’s fine.

Exp Win Explanation

The home team has a 52.4% chance of winning on the odds. We know this is inflated to account for the bookmaker’s margin. Take 3% away from each of the three outcomes to account for this and the home team now has a 49.4% chance of winning. So using the above quoted odds we get an Exp win of 0.49 for the home team (priced at 10/11) and 0.42 for the away team (priced at 6/5).

Do this for all games for a particular team and you have created an Expected Wins metric.